Depending on whether you have ever gotten wireless reception in that room, you may simply be too far from your router. Both signal strength and throughput go down rapidly the further you get from a wireless router, especially if there is a lot of intervening building structure and metal. Depending on the configuration of your place, you might want to try putting both your router and the computer in question by the nearest windows, as the signal may travel further outside than inside (though that didn't work for me). I have 50 Mb/s FIOS with a brand new extended range (Quantum) wireless router on the second floor of my home and the signal in the basement two floors directly below it was barely enough to support a constant connection. Many larger or spread out homes have dead spots for wireless.
If that's the case, there is a whole range of wireless signal extenders and repeaters for sale that can help with the problem, if you can't move your router or your computer closer.
But for us the solution was simpler as we had a coax cable connection in the basement (for the TV) and we bought a $80 Actiontech wireless network extender from Verizon for the basement. It communicates automatically with their router by cable, and became a secondary wireless signal source in the basement, with no appreciable loss of bandwidth or signal.